Hydraulic pump



L. R. MYERS HYDRAULIC PUMP May 14, 1968 Filed June 30, 1966 I N VEN TOR. LAWRENCE 1?. MYEES 9) w @wsm Q w R Wm Nw 3 A T TOENE Y United States Patent ABSTRACT OF THE DISCLOSURE A ported induction pump with a pressure responsive means formed with differential areas subjected to discharge pressure flow from the output such that working pressure in the pump chamber and the larger of the areas of the pressure responsive means regulates the position of the inlet port for the pumping chamber.

This invention relates to a pressure regulating device for a ported induction pump.

It is a principal object of this invention to provide a pressure regulating ported induction pump design that is simpler and has fewer parts than any similar pump presently known so that it is more economical to manufacture and maintain.

It is a further object of this invention to provide a hydraulic pump with a positive regulation of discharge pressure by the elimination of creeping due to leakage.

It is a still further object of this invention to provide a differential area pressure regulating device for positioning a pumping cylinder to relieve working pressures whenever the discharge pressure has reached a predetermined level.

Other objects and advantages of this invention will be observed by those skilled in the art to which it relates from the figure showing a cross sectional detail of a pump designed in accordance with the principles of this invention.

More particularly, with regard to the figure, there is shown a pump having a housing 12 with an internal chamber 14 open at one end, as at 16. The chamber 14 is provided with a fluid inlet port 18 and a fluid discharge port 20. A shaft (not shown) is rotatably mounted through the housing so that an eccentric 22 is revolvable thereby within the chamber 14. A pitman 24 is operatively connected to the eccentric 22 so as to be reciprocated upon the revolution thereof.

Within the chamber a cylinder 26 is reciprocally arranged, and a plunger 28 is connected to a spherical socket 30 and the pitman 24 by means of a spring 32. The plunger 28 reciprocates within a bore or pumping chamber 34 of the cylinder 26, and in the rest position normally lies adjacent the rear face of a radial passage 36 leading internally of the cylinder 26 from slots 38 about the periphery of the cylinder. A disc type valve 40 is pressed against a forward face for the bore 34 by means of a spring 42 upon the assembly of a stepped projection 44 to the cylinder 26, as by threading it and the cylinder together.

The stepped projection 44 is arranged within a collar 46 having a stepped bore 48 which is open to a radial passage 50 through the collar communicating with the outlet port 20. As may be appreciated, seals are incorporated within the collar to prevent fluid leakage from the chamber 14 beyond the collar 46.

A plug 51 is screwed into the housing at the open end of the chamber 14. This plug is provided with an adjustable spring retainer 52, and a spring 54 is loaded by the assembly of the plug 51 and retainer 52 to the housing 12 so as to place a load upon the stepped projection 44 which in turn normally positions the cylinder 26 against a shoulder 56 of the housing 12 within the chamber 14. The plug 51 positions the collar 46 against a shoulder 57 in the housing 12.

3,3823% Patented May 14, 1968 In operation, fluid enters the pump through the inlet 18 and into the chamber 14. This fluid thru the passages 38 about the cylinder 26 to suspend the cylinder in inlet pressure. When the piston is in the position shown in the drawing, the fluid flows into the radial passage 36 to the pumping chamber 34. Thereafter, upon revolution of the eccentric 22 the pitman 24 is reciprocated to translate the plunger or piston 28 within the pumping chamber 34 to first close the radial passage 38 and thereby pre'surize the chamber 34 so that the valve 40 may be opened against the pressure of spring 42. It should be understood, that as the piston retracts, it relieves the pressure in the chamber 34 so that the valve 40 closes and more fluid will enter the chamber through the passageway 36 whereupon the piston 28 is ready for another cycle.

Meanwhile, the fiuid pumped through the valve 49 flows through the passage 58 within the stepped projection 44 to the radial passage 60 and out to a stepped chamber formed between projection 44 and bore 48 in the collar 46. All this time, the regulating spring 54 and the friction of the seals 62 and 64 on the projection or regulating piston 44, as it may be termed, hold the regulating piston and the cylinder in a pumping position. When the outlet pressure builds up to a predetermined level, a force is created on the larger area 66 of the projection 44 as well as upon the smaller area 68 thereof. However, the pressure on the larger area 66 plus the force of the piston 28 compressing the fluid when above the aforementioned predetermined level overcomes the regulating spring 54 and the pressure acting on the smaller area 68. Whereupon, the projection 44 and the cylinder 26 move to the left, as viewed in the drawings. This movement places the cylinder 26 in a position relative to the piston whereupon the radial passage 36 cannot be closed by the reciprocation of the plunger or piston 28 and pressure cannot, therefore, be built within the pumping chamber 34.

It should also be understood, that, if the pressure at the outlet 20 is reduced enough to allow the regulating spring to overcome the aforementioned forces, the regulating piston or projection 44 moves the cylinder 26 back into a pumping position.

Having fully described a construction of a preferred embodiment of my invention as well as the operation thereof, is is now desired to set forth the scope of protection sought by these Letters Patent in the following claims.

I claim:

1. A pump comprising:

a housing having a chamber therein open at one end with inlet and outlet ports;

a cylinder slidably mounted in said chamber, said cylinder having a bore therethrough and a radial passage communicating said bore to a fluid passageway between said housing and said cylinder which is open to said inlet port so that said cylinder is suspended in inlet fluid pressure;

a reciprocating plunger operatively arranged in said chamber for reciprocation in said bore of said cylinder;

a pressure responsive valve means closing said bore of said cylinder at the end thereof opposite that receiving said plunger;

a collar aflixed to said housing, said collar having a stepped opening therethrough, said collar provided with seal means at each end of said stepped opening therethrough and having a radial passage intermediate the stepped opening therethrough that is located to communicate with said outlet port of said housing;

a stepped projection removably aflixed to said cylinder and extending therefrom through said collar such 1:; 4 that said stepped projection and said stepped opennme chamber as assisted by the pressure in said bore ing form a variable volume chamber defined by said of said cylinder. seal means at each end of said stepped opening, said projection having a fluid passage means operatively Referaflces Cited connected to said bore of said cylinder behind said 5 UNITED STATES PATENTS pressure responsive valve means for communicating said bore to said variable volume chamber about 2O10165 8/1935 Tear, 1O3 37 the stepped projection in said collarand 3117524 1/1964 Budzlch 103-37 3,183,847 5/1965 Raymond 103-37 an adjustable spring means operatively connected to said projection, said means being removably afiixed to said housing at its open end for positioning said 10 ROBERT WALKER Pnmary Exammer' projection and in turn said cylinder in said chamber LAURENCE V. EFNER, Examiner. in accordance with the pressure in said variable vol- 

